text: UF is prepared from UO in a fluidized bed by reaction with HF. The UO is derived from mining operations. Around 60,000 tonnes per year are prepared in this way annually. A common impurity is UOF. UF4 is susceptible to hydrolysis as well.
  UF is formed by the reaction of UF with hydrogen gas in a vertical tube-type reactor.
  UF is less stable than the uranium oxides and reacts slowly with moisture at ambient temperature, forming UO and HF, the latter of which is very corrosive and toxic; it is thus less favourable for long-term disposal. The bulk density of UF varies from about 2.0 g/cm to about 4.5 g/cm depending on the production process and the properties of the starting uranium compounds.
  A molten salt reactor design, a type of nuclear reactor where the working fluid is a molten salt, would use UF as the core material. UF is generally chosen over other salts because of the usefulness of the elements without isotope separation, better neutron economy and moderating efficiency, lower vapor pressure and better chemical stability.